Some conventional motor drive apparatuses have a plurality of motor drive parts. According to an electric motor drive apparatus disclosed in the following patent document 1, for example, a motor driver and a motor winding form a motor drive part and two motor drive parts are provided. Thus, the motor is operated to generate drive force, whichever winding of the motor drive part is energized.    Patent document 1: JP H7-33033
In some of the motor drive apparatuses having the plurality of motor drive parts, the plurality of motor drive parts is arranged in parallel to provide large rotational torque. The total value of the rotational torque provided to drive the motor is determined as a sum of rotational torque values of all the motor drive parts.
In case of generating large rotational torque in the motor drive apparatus, a large current need be supplied to the motor. The motor drive parts therefore are required to control large currents. If a certain failure occurs in the motor drive apparatus for some reasons, a large current will unexpectedly flow. It is therefore general practice to start driving the motor after checking for any failure in each of the motor drive parts.
If the motor id driven after completing the failure check operation with respect to each motor drive parts by the motor drive apparatus, the failure check operation will be completed at different time points among the plurality of motor drive parts and hence the motor drive parts will start to drive the motor at different time points. In this case, some of the drive parts will not be able to provide the rotational torque at a time point immediately after starting the motor drive operation. As a result, the motor will not be able to generate the initially determined torque, which corresponds to the sum of the drive forces of the motor drive parts, for a certain period. That is, the motor will not be able to be driven and controlled appropriately for the certain period immediately after the motor drive operation is started.